The present invention relates to a power supply base for an alarm device, in particular a fire alarm or smoke alarm.
The present invention also relates to a method for setting up the power supply base of the invention.
Below, fundamental problems that the invention is response to are described, based on power supply bases for fire alarms, but without limiting the subject to power supply bases of that kind.
A fire alarm is known from International Patent Disclosure WO 97/05586, among other sources. These fire alarms typically comprise two parts, namely a power supply base and a fire sensor. The power supply base can be mounted on the ceiling and is connected by power supply lines to a fire-detection-system control unit. The fire sensor is inserted into the power supply base by technicians.
Typically, many fire alarms, in a series circuit or serial topology, are connected to a fire-detection-system control unit 1 (FIG. 1). For safety reasons, it is necessary that the fire-detection-system control unit 1 be able to tell whether all the fire sensors 2 are functional and in particular have been inserted into the associated power supply bases 3. This requirement is met by providing that each power supply base 3 internally interrupts the power supply line 4. Not until a fire sensor 2 is inserted does it connect to internal terminals 5, 6 of the power supply base 3. The interruption in the power supply line is thus bridged by the fire sensors 2. If one or more fire sensors 2 is missing, the power supply line 4 is interrupted. This interruption can be detected, for instance by means of a resting current measurement in the central warning system 1. Typically, a termination resistor 7 connects the power supply line 4 to a return line 8.
The resting current measurements and perfect function of the alarms, however, function only with correct wiring of the power supply bases 3 beforehand. It is therefore desirable to be able to check the correctness of the wiring even before any alarms have been inserted. This reduces the effort and expense for looking for mistakes in the event of incorrect wiring in particular.